Hey guys I'm in the process of trearing down my 68 360, it has c8ae-h heads, thinking of going with a scat crank kit for the bottom end. I want to keep it pump gas. Not sure on the intake yet, but I have a Holley 680cfm carb and headers. Would it be worth building the motor with stock head? Any Idea what kind of Hp I would be looking at with an aggressive cam, and stock heads With the 445 assembly.

 

It's going to have more torque overall, the heads will limply limit the topend rpms. Something you will probably want to do anyway to avoid overstressing the block. It all depends on what you expect out of the finished product.

 

If you can hold on to 400 ft/lbs of torque to 5500 rpm, you will have about 420 HP. 5500 being a good place to stop with stock heads. You might be able to to 6000, but the torque is going to drop off as you go up, so probably not much different.

Why fool with stock heads if you are doing an engine like this? Someone rebuild those C8s recently, new guides, good seals, hardened seats? You will need new springs and other parts with that cam.

Just follow the recipe and build a proven motor, not something with a major compromise built into it. As for pump gas, you can select your compression ratio, match it up with the cam, and with aluminum heads, run pump gas no problem. Maybe even the off brand regular grade swill stuff:

Survival FE Engine Kits

 

I would like the stock heads for Astetics mostly it's going in a 47 half Ton fender less truck. I know the heads will be a big Hp set back in revs but I could always do them after the affect as well. This is my first fe build. I want to hit the 400+ mark but still look fairly stock. But if I can hit 420 at 5500 that will more than propell the little chopped 47. Thanks

 

Aluminum heads look better IMO, but you can always paint them. Iron or aluminum, the question with the C8s is are the usable without $500-700 worth of work?

 

Shame BarryR isn't here anymore, he recently posted a bunch of stock head stroker builds that were really nice power wise at the other place.

 

In a lightweight, seldon driven street truck, the iron heds will do fine, and you can still run it on pump gas. No more than it'll be driven, hardened seats aren't a requirement. Just use a lead substitute to mitigate any possible seat wear (I doubt there'll be any anyway) Just stroking it to a 390 will give it more power than you may want.

 

I tried that on my 428CJ, less than 2,000 miles a year and luckily caught the heads just in time not to suck a valve and ruin a set of cj heads. For the cost get the hardened seats and then you don't have to worry about it. Peace of mind is priceless.

 

I ran my last 390 just this way (adding lead substitute) seat recession was never an issue on it's C8AE-H heads.

 

Been there, done that and with premium fuel and lead additive. No more, as I said peace of mind. If I hadn't torn the Mustang down for a full restoration I'd have been looking for new heads on a numbers matching, single owner"me" 69 Mustang, Mach 1 with 428 cj power.

 

You are both right. Some motors go fine on unleaded, some eat the seats in short order. This happened new also. Our '66 had a burned valve at 41,000 miles. So to the OP, you slap it together, you take your chances.

 

Sometimes those ar ethe most reliable engines. Same goes for those meticulously put together. Sometimes those don't turn out so well either because of hidden flaws.

 

I'm not saying you are wrong but apparently you have a major problem admitting that you can be wrong. Perfection is hard to have an intelligent conversation with.

 

I'm just as "right" as you are. You had a problem with seat recession, I didn't. That does not make me wrong. That just makes it hard for you to deal with a problem that you cannot seem to comprehend. I had another 390 in the late 80's that too, didn't have hardened seats (67 GT390 heads) and never had a problem with seat recession either. And the gas at that time was far worse in quality than we have today. I'm no smarter than the average guy, but certainly I don't have a problem such as you now seem to be having. Don't get your panties in a wad when someone else gives advice contrary to what you have given.

 

Once again I will plug spending $49 on Desktop dyno 5 , you can mix match all kind of parts to see what HP TQ numbers you get . then buy your parts .

amazon has it